Bug 1587574 - Add test for fieldInitializers lookup r=jorendorff

Differential Revision: https://phabricator.services.mozilla.com/D48756

--HG--
extra : moz-landing-system : lando

js/src/tests/non262/fields/bug1580246.js

@@ -0,0 +1,14 @@
+// Don't Crash
+var testStr = `
+class C extends Object {
+  constructor() {
+    eval(\`a => b => {
+      class Q { f = 1; }  // inhibits lazy parsing
+      super();
+    }\`);
+  }
+}
+new C;`
+assertEq(raisesException(ReferenceError)(testStr), true);
+
+reportCompare(true, true);